In general, an actuator is a type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, typically electric current, hydraulic fluid pressure, or pneumatic pressure, and, in turn, converts that energy into motion. An actuator is the mechanism by which a control system, such as a mechanical or electronic system, acts upon an environment. Specifically, an actuator can be employed for controlling operation of a piece of equipment, such as a valve or a lock.